Field Notebook: Texas 1957b
Page 11
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The SE 20'-30' seem to be faulted down about 10'; It should make no difference because this section was measured on the SE side of this fault. {note: illustration followed}. PG.9 Collection 8/5/57/9 - Collection from a Gaptank calcarenite fairly high in section, but exact position stratigraphically not known. On examining P.King's map and text this unit may be lowest gray granular limestone at the base of the Gaptank. Concerning section 24, what is Wolfcamp and what is Hess; if we take the conglomerate section (#17) as the base the Hess, where do the lower limestone beds fit - luckily the fusulines should help a lot. There is no Wolfcamp conglomerate here or at least none cropping out. If it is here it must be very thin. The cobbles in section 25 on outward appearance seem to represent some of the rocks in this limestone sequence. This will bear further checking. PG. 10 Section 25, NE end of Dugout Mt. Ridge; Measured on line N22°E from tin shack, dip here is variable but between 15° to 30° to the NNE in the Wolfcamp conglomerate. 1) Covered, probably Gaptank. 2) Calcarudite, lowest certain bedrock exposure, much sand (brown) and chert pebbles, at least 140' thick, probably about 160' including changes of dip and covered base. Collection 8/5/57/10 (2 bags) at about 110'. 3) Covered, 12', perhaps conglomerate, maybe not. ?top of Lenox Hills Fm.?. 4) Conglomerate, chert, quartzite % increase over limestone. Brown sands more apparent. 15'. Collection 8/5/57/11. 5) Conglomerate and covered intervals. This is down a dip slope with a number of folds and faults. I estimate the thickness of conglomerate here to be 150'. The upper beds become more calcic and the amount of organic fragments increase greatly, a few beds are calcarenites and some are sandstones (very fine) and shale and silts. PG. 11 These form a transition in the upper 40' into the next unit. {note: illustration followed} To be continued! - [but it wasn't] PG. 12 8/6/57 Section 24 (4) - up Highest point on Dugout Mt. covered below - contact with Gaptank Fm. not visible. 1) Conglomerate, large boulder 10"-17" diameter are common. The larger ones are limestone, but many smaller pebbles are chert and quartzite (fracture pattern of rock). Thickness at least 30'. 2) Sandstone, light yellow and brown, friable, very fine sand, poorly cemented with calcite. 4'.